The retired U.S. Marine general, speaking at a Reuters Newsmaker event in New York, said the United States should generally side with those standing up for human rights, which he said included the Hong Kong protesters.

“When people stand up for those (rights), I just inherently think we ought to stand with them, even if it’s just moral,” said Mattis, who abruptly resigned as Pentagon chief in December over disagreements with President Donald Trump’s foreign policy.

“This is not an internal matter,” Mattis said in remarks likely to irritate Beijing, which has denounced the sometimes violent protests and accused the United States and Britain of fomenting unrest in the former British colony.